新元古代岩浆Ni-Cu-(PGE)硫化物矿床地质特征、形成时代及其地球动力学背景

Geological characteristics,geochronology and tectonic settings of Neoproterozoic magmatic Ni-Cu-(PGE) sulfide deposits in China

岩浆硫化物矿床已成为矿床学研究的热点之一。罗迪尼亚（Rodinia）超大陆的汇聚与裂解受到国际地学界的广泛关注，通过对中国新元古代岩浆Ni—Cu-（PGE）硫化物矿床的研究，将有助于推动Rodinia研究的深入。最新的SHRIMP锆石U-Pb法和硫化物矿石Re-Os法定年结果表明，宝坛、煎茶岭、冷水箐和金川Ni—Cu-（P（正）硫化物矿床均形成于新元古代早期（1000-800Ma），且从南到北、从东到西．成矿时代依次变新，即从宝坛（982±21）Ma→煎茶岭（878±27）Ma→冷水箐（约800Ma）→金川（833±35）Ma，而矿床规模从宝坛中型Ni-Cu-Co-（PGE）矿床→煎茶岭大型Ni—Co矿床→冷水箐中型Ni-Cu-（PGE）矿床→金川超大型Ni—Cu-Cp（PGE）矿床，这些矿床均处于克拉通边缘，即扬子克拉通南缘、北缘和西缘以及华北克拉通西南缘。中国新元古代岩浆Ni—Cu-（PGE）硫化物矿床按其所处的大地构造位置可划分为桂北、勉略宁、盐芦和龙首山等4个成矿带，且它们的形成均与Rodinia超大陆的拼合与裂解密切相关。

98% Pt, 86% Ni and 7.5% Cu of China come from magmatic sulfide deposits. Therefore, the study of these deposits becomes one of the mcst active research subjects. The convergence and divergence of Rodinia supercontinent have aroused extensive attention among geoscientists all over the world, and the investigation of Neoproterozoic Ni-Cu-（PGE） sulfide deposits in China will be surely helpful to the deepgoing study of Rodinia supercontinent. The available zircon U-Pb dating and Re-Os dating data of sulfide ore deposits show that the metallogenic events of Baotan, Lengshuiqing, Jianchaling and Jinchuan Ni-Cu-（PGE） sulfide deposits all occurred at the early stage of Neopmterozoic （1 000-800 Ma）. From south to north, the metallogenetic epoch of the four deposits became younger and the metallogenic dimensions became larger, that is, from （982 ± 21 ） Ma of Baotan to （878 ± 27）Ma of J ianchaling to （833 ± 35） Ma of Jinchuan to （800 ± ） Ma of Lengshuiqing, the ore-forming process is from middle to large to superlarge in scale. The four deposits are all the break-up products of Neoproterozoic Rodinia Supercontinent and they are distributed on the margin of the craton, i.e., on the southwestern margin of the North China Craton and on the western, northern and southern margin of the Yangtze Craton. These sulfide deposits may be divided into four metallogenic belts, namely. Longshoushan belt, Yanlu belt, Mianluening belt and Guibei belt, with the corresponding geodynamic settings being the rift environment cracked by the North China Plate, the island arc environment on the margin of the Yangtze Plate, the extensional environment after collision and post-orogeny of the Yangtze Plate and the North China Plate, and the arc-rear extensional environment on the margin of the Yangtze Plate.